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    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    
        h1,div,p,li{
            width: 300px;
            background-color: gold;
        }
    
    
    </style>
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<body>
    

    <h1>一级标题</h1>
    <div>div1</div>
    <p>pp1p1p1p1p1</p>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
    </ul>
    

</body>
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